Abstract: A system for maintaining a high vacuum in a vacuum enclosure such as cryostat, for example, is described. The system includes a high-vacuum pump having an input that is connected to the cryostat and an output. A vacuum vessel is connected to the output of the high-vacuum pump. A second vacuum pump is connectable to the vacuum vessel. The system is operated such that the high-vacuum pump maintains the cryostat at a high vacuum and the second vacuum pump is periodically operated to maintain the pressure of the vacuum vessel below a threshold pressure. The second vacuum pump may be either permanently connected to, or removable from, the vacuum vessel. The vacuum vessel acts to maintain the output of the high-vacuum pump within a suitable pressure range. This removes the need for the output of the high-vacuum pump to be connected to a continuously operating, second-stage vacuum pump.

Abstract: An ac synchronous electrical machine includes a stator and a multi-phase stator winding that defines a plurality of stator poles. The stator winding has two or more coil groups, each coil group including a plurality of coils for each phase that are received in winding slots in the stator. The stator winding is connected to a power source/sink. The coil groups are connected in series and each coil group is connected to a power source/sink by a respective switch (26a, 26b . . . ). This allows one or more of the coil groups to be selectively supplied with power from the associated power source/sink or selectively supply power to the associated power source/sink. The switches are operated by a controller. The coils in each coil group are arranged substantially symmetrically around the circumference of the stator to define selected poles of the electrical machine and to produce a constant and balanced rotating torque when any particular coil group or combination of coil groups is active.

Abstract: An assembly includes an electrical machine connected to a power converter by a three-phase circuit having three conductors, e.g. cables Each conductor is associated with a switching device such as a contactor or the like that connects the conductor to a common conductor or terminal. In the event of a fault current being developed in the circuit or the power converter the switching devices are operated to close the fault current and connect together the conductors of the three-phase circuit to provide a full three-phase short circuit.

Abstract: A power supply system for a charge is provided. The power supply system includes a converter connected in input to a current source and in output to a charge, the converter being able to deliver a direct current to the charge and allow the circulation of the current in a single direction, from the current source to the charge and a circulation bus for an electric current, including a first end and a second end. The power supply system further includes a device for injecting an additional alternating voltage and at the second end of the circulation bus, the injection device being connected to the second end and a device for recovering the additional injected alternating voltage, the recovery device being connected between the first end of the bus and the charge, so as to supply the charge with electrical current.

Abstract: In a marine power distribution and propulsion system with a medium voltage distribution busbar (MVAC1) and a low voltage distribution busbar (LVAC1) then a rectifier (SC) is controlled, optionally to provide active filtering and static compensation benefits. A common power supply system incorporating ac generators (G1-G4) supplies power to the medium and low voltage distribution busbars. The rectifier (SC) is connected to the medium voltage distribution busbar (MVAC1). A controller (Co) uses feedback signals indicative of electrical quantities of the distribution voltages carried by both the medium voltage and low voltage distribution busbars (MVAC1, LVAC1) to control the rectifier (SC) to regulate electrical quantities at the ac terminals of the rectifier (SC) in order to achieve desired electrical quantities of the distribution voltage carried by the low voltage distribution busbar (LVAC1).

Abstract: A semiconductor module comprising a plurality of electrically conductive top plates, an electrically conductive base plate, a plurality of semiconductor chips installed on the base plate, a first power supply connected to the plates, a second power supply connected to the plates and an electrically insulating outer casing component. The semiconductor chips are individually in contact with the top plates. Each semiconductor chip comprises a first electrode electrically coupled with the base plate, and a second electrical pole electrically coupled with the corresponding top plate. The first power supply connecting plate is equipped with protruding parts that are individually in electrical contact with the top plates. The second power supply connecting plate is electrically connected to the base plate. The outer casing component is used to integrate the first power supply connecting plate and the second power supply connecting plate. The outer casing component comprises at least one opening.

Abstract: Provided is a series capacitor for controlling a flow of power on a transmission line, and includes a filter circuit, and a thyristor-controlled circuit, wherein an interconnection and operation of the filter circuit and the thyristor-controlled circuit are performed based on a coordination of control thereof, to connect to a series capacitor bank on a transmission line.

Abstract: A method for switching the voltage supply for an alternating current electric engine between a supply from an ASD and a supply from an electrical network, the method comprises a stage for determining an ideal speed of rotation for the electric engine and for synchronizing the phase and the amplitude of the voltage delivered by the ASD with the voltage delivered by the electrical network.

Abstract: A system for converting a first electric voltage into a second electric voltage, comprising: at least two input terminals and two output terminals; and switching members disposed between the terminals, which can convert the first voltage into the second voltage. At least one switching member comprises at least two arms connected in parallel and each arm includes an electronic switch that can be controlled such as to occupy either an on-state or an off-state, said switch comprising a control electrode and two conduction electrodes that conduct current in the on-state. The switching member comprises a common control terminal connected to the control electrode of the switch of each arm, as well as a first common conduction terminal and a second common conduction terminal connected respectively to a first conduction electrode and a second conduction electrode of the switch of each of the arms.

Abstract: An axial flux machine comprising a rotor mounted about an axis of rotation and having two axial faces. A first stator ring is positioned on the rotor adjacent to a first axial face, to define an air gap, between the first stator ring and first axial face. The first stator ring is formed by stator ring segments, each having a radially inner and outer edge. A second stator ring is positioned on another side of the rotor, adjacent to the second axial face, to define an air gap between the second stator ring and second axial face. The second stator ring is, also, formed by stator ring segments, each having a radially inner and outer edge and corresponding to a first stator ring segment. The stator ring segments are deflectable in unison in response to axial deflection of the rotor, to maintain the air gaps, due to link elements.

Abstract: Provided is an approach for active control of cross currents flowing among multiple paralleled converters. Control of cross currents is achieved by using at least one proportional-integral (PI) controller and at least one resonant controller to target several selected dominant harmonics with infinite gains to ensure elimination of targeted harmonic cross currents in steady state. The cross currents are decomposed by into (1) common mode and differential mode components or (2) current phase domain components and each component is suppressed to a value approximately near zero using the controller. Also provided is a device comprises instructions, that, when executed by a processor, cause the processor to perform operations, which regulate and suppress cross current within a power system.

Abstract: An electric machine is provided. The electric machine includes at least one stator, a shaft, movable in rotation around an axis of rotation, two rotors, each being interdependent of the shaft, at least two bearings, able to support both rotors and the shaft. A single bearing is located between both rotors along the axis of rotation.

Abstract: An assembly includes an electrical machine connected to a power converter by a three-phase circuit having three conductors, e.g. cables Each conductor is associated with a switching device such as a contactor or the like that connects the conductor to a common conductor or terminal. In the event of a fault current being developed in the circuit or the power converter the switching devices are operated to close the fault current and connect together the conductors of the three-phase circuit to provide a full three-phase short circuit.

Abstract: A gas treatment machine includes a main gas treatment circuit, connected to a gas compression chamber, a gas compressor, mounted in the compression chamber, a rotating electrical machine, for driving the gas compressor, including at least one coil for the flow of electric current for generating a magnetic flux, and a secondary cooling circuit, transporting gas from the compression chamber to the rotating electrical machine, for cooling this rotating electrical machine. The coil includes at least one toroidal core formed from a rolling of a plurality of turns (20) each consisting of at least one conductor (22) insulated over the length thereof by a primary insulator (24), the rolling which forms the toroidal core in turn being covered with a secondary insulator (26), the primary insulator (24) and the secondary insulator (26) including PolyEtherEtherKetone.

Abstract: A mechanical assembly such as a torque transfer strut for a rotating superconducting machine. The torque transfer strut includes a composite tube having a first end received in a clamping fitting, which may include an end housing or lug, a clamping wedge screwed onto a threaded end housing, and an annular clamping member applying a radial clamping force to the first end of the composite tube at ambient temperature. When cooled, shrinkage of the end housing in the axial direction causes the annular clamping member to maintain or increase radial clamping force, causing the clamping wedge to apply increasing radial force to an inner member deflecting outwardly a plurality of axial fingers. The first end of the composite tube remains clamped between the inner member and an outer member, together defining an annular channel receiving the first end of the composite tube.

Abstract: A semiconductor device or power electronic device is described. The device includes a pair of pole pieces, each having a profiled surface. A semiconductor body or wafer, preferably of wide bandgap electronic material, is located between the pole pieces and includes contact metallization regions. The semiconductor body produces an electric field that emerges from an edge region. Passivation means includes a first or radially inner part in contact with the edge region of the semiconductor body and which diffuses the electric field as it emerges from the edge region and a second or radially outer part. The second part of the passivation is in contact with the first part and provides a substantially void-free interface with the profiled surface of each pole piece. The device may be immersed in a dielectric liquid.

Abstract: A device includes a transformer configured to supply a pre-charge voltage to a capacitor and a converter configured for coupling to the transformer and responsive to an increasing modulation index. The modulation index increases for a time quanta after the capacitor becomes substantially fully charged and the pre-charge voltage is substantially constant during the time quanta.

Abstract: A method of operating a dual fed system is described where power is supplied to a electrical load from first and second ac busbars at a ratio that achieves a desired level of exhaust emissions such as nitrogen oxides (NOx), carbon dioxide (CO2) and other pollutants produced by the prime movers associated with generators. Preferably, the method may be used to operate a dual fed marine propulsion system wherein the electrical load is a thruster. Operating a dual fed marine propulsion system using the method of the present invention makes it possible to optimize thrust allocation between thrusters in a way that is similar to that used in conventional dynamic positioning (DP) systems and then share or allocate the required power between generators to minimize exhaust emissions.

Abstract: A method of controlling a plurality of power converters 1a, 1b and 1c can be used to interface to a supply network, ac busbar etc. Each power converter includes a network bridge 14 operating in accordance with a pulse width modulation (PWM) strategy having the same switching period and which causes at least one unwanted harmonic in the supply network voltage. The method includes the step of providing the switching period of the PWM strategy of each network bridge with a different time offset relative to a time datum such that the at least one unwanted harmonic in the supply network voltage is at least partially cancelled. Two alternative ways of providing the time offset are described.

Abstract: The invention relates to a component such as a rotor or stator for an electrical machine. The component includes a plurality of axially adjacent stacks of laminations. At least one pair of adjacent stacks are spaced apart in the axial direction by spacer means such that a passageway or duct for cooling fluid, e.g. air, is formed therebetween. The spacer means comprises a porous structural mat of metal fibers. The cooling fluid may flow through the spaces or voids between the fibers.